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    Subject[PATCH 10/20 take 4] UBI: EBA unit
    diff -auNrp tmp-from/drivers/mtd/ubi/eba.c tmp-to/drivers/mtd/ubi/eba.c
    --- tmp-from/drivers/mtd/ubi/eba.c 1970-01-01 02:00:00.000000000 +0200
    +++ tmp-to/drivers/mtd/ubi/eba.c 2007-03-23 18:20:01.000000000 +0200
    @@ -0,0 +1,1132 @@
    +/*
    + * Copyright (c) International Business Machines Corp., 2006
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + *
    + * This program is distributed in the hope that it will be useful,
    + * but WITHOUT ANY WARRANTY; without even the implied warranty of
    + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
    + * the GNU General Public License for more details.
    + *
    + * You should have received a copy of the GNU General Public License
    + * along with this program; if not, write to the Free Software
    + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
    + *
    + * Author: Artem Bityutskiy (Битюцкий Артём)
    + */
    +
    +/*
    + * The UBI Eraseblock Association (EBA) unit.
    + *
    + * This unit is responsible for I/O to/from logical eraseblock.
    + *
    + * Although in this implementation the EBA table is fully kept and managed in
    + * RAM, which assumes poor scalability, it might be (partially) maintained on
    + * flash in future implementations.
    + *
    + * The EBA unit implements per-logical eraseblock locking. Before accessing a
    + * logical eraseblock it is locked for reading or writing. The per-logical
    + * eraseblock locking is implemented by means of the lock tree. The lock tree
    + * is an RB-tree which refers all the currently locked logical eraseblocks. The
    + * lock tree elements are &struct ltree_entry objects. They are indexed by
    + * (@vol_id, @lnum) pairs.
    + *
    + * EBA also maintains the global sequence counter which is incremented each
    + * time a logical eraseblock is mapped to a physical eraseblock and it is
    + * stored in the volume identifier header. This means that each VID header has
    + * a unique sequence number. The sequence number is only increased an we assume
    + * 64 bits is enough to never overflow.
    + */
    +
    +#include <linux/slab.h>
    +#include <linux/crc32.h>
    +#include <linux/err.h>
    +#include "ubi.h"
    +
    +/**
    + * struct ltree_entry - an entry in the lock tree.
    + * @rb: links RB-tree nodes
    + * @vol_id: volume ID of the locked logical eraseblock
    + * @lnum: locked logical eraseblock number
    + * @users: how many tasks are using this logical eraseblock or wait for it
    + * @mutex: read/write mutex to implement read/write access serialization to
    + * the (@vol_id, @lnum) logical eraseblock
    + *
    + * When a logical eraseblock is being locked - corresponding &struct ltree_entry
    + * object is inserted to the lock tree (@ubi->ltree).
    + */
    +struct ltree_entry {
    + struct rb_node rb;
    + int vol_id;
    + int lnum;
    + int users;
    + struct rw_semaphore mutex;
    +};
    +
    +/* Slab cache for lock-tree entries */
    +static struct kmem_cache *ltree_slab;
    +
    +/**
    + * next_sqnum - get next sequence number.
    + * @ubi: UBI device description object
    + *
    + * This function returns next sequence number to use, which is just the current
    + * global sequence counter value. It also increases the global sequence
    + * counter.
    + */
    +static unsigned long long next_sqnum(struct ubi_device *ubi)
    +{
    + unsigned long long sqnum;
    +
    + spin_lock(&ubi->ltree_lock);
    + sqnum = ubi->global_sqnum++;
    + spin_unlock(&ubi->ltree_lock);
    +
    + return sqnum;
    +}
    +
    +/**
    + * ubi_get_compat - get compatibility flags of a volume.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + *
    + * This function returns compatibility flags for an internal volume. User
    + * volumes have no compatibility flags, so %0 is returned.
    + */
    +static int ubi_get_compat(const struct ubi_device *ubi, int vol_id)
    +{
    + if (vol_id == UBI_LAYOUT_VOL_ID)
    + return UBI_LAYOUT_VOLUME_COMPAT;
    + return 0;
    +}
    +
    +/**
    + * ltree_lookup - look up the lock tree.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + *
    + * This function returns a pointer to the corresponding &struct ltree_entry
    + * object if the logical eraseblock is locked and %NULL if it is not.
    + * @ubi->ltree_lock has to be locked.
    + */
    +static struct ltree_entry *ltree_lookup(struct ubi_device *ubi, int vol_id,
    + int lnum)
    +{
    + struct rb_node *p;
    +
    + p = ubi->ltree.rb_node;
    + while (p) {
    + struct ltree_entry *le;
    +
    + le = rb_entry(p, struct ltree_entry, rb);
    +
    + if (vol_id < le->vol_id)
    + p = p->rb_left;
    + else if (vol_id > le->vol_id)
    + p = p->rb_right;
    + else {
    + if (lnum < le->lnum)
    + p = p->rb_left;
    + else if (lnum > le->lnum)
    + p = p->rb_right;
    + else
    + return le;
    + }
    + }
    +
    + return NULL;
    +}
    +
    +/**
    + * ltree_add_entry - add new entry to the lock tree.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + *
    + * This function adds new entry for logical eraseblock (@vol_id, @lnum) to the
    + * lock tree. If such entry is already there, its usage counter is increased.
    + * Returns pointer to the lock tree entry or %-ENOMEM if memory allocation
    + * failed.
    + */
    +static struct ltree_entry *ltree_add_entry(struct ubi_device *ubi, int vol_id,
    + int lnum)
    +{
    + struct ltree_entry *le, *le1, *le_free;
    +
    + le = kmem_cache_alloc(ltree_slab, GFP_KERNEL);
    + if (unlikely(!le))
    + return ERR_PTR(-ENOMEM);
    +
    + le->vol_id = vol_id;
    + le->lnum = lnum;
    +
    + spin_lock(&ubi->ltree_lock);
    + le1 = ltree_lookup(ubi, vol_id, lnum);
    +
    + if (le1) {
    + /*
    + * This logical eraseblock is already locked. The newly
    + * allocated lock entry is not needed.
    + */
    + le_free = le;
    + le = le1;
    + } else {
    + struct rb_node **p, *parent = NULL;
    +
    + /*
    + * No lock entry, add the newly allocated one to the
    + * @ubi->ltree RB-tree.
    + */
    + le_free = NULL;
    +
    + p = &ubi->ltree.rb_node;
    + while (*p) {
    + parent = *p;
    + le1 = rb_entry(parent, struct ltree_entry, rb);
    +
    + if (vol_id < le1->vol_id)
    + p = &(*p)->rb_left;
    + else if (vol_id > le1->vol_id)
    + p = &(*p)->rb_right;
    + else {
    + ubi_assert(lnum != le1->lnum);
    + if (lnum < le1->lnum)
    + p = &(*p)->rb_left;
    + else
    + p = &(*p)->rb_right;
    + }
    + }
    +
    + rb_link_node(&le->rb, parent, p);
    + rb_insert_color(&le->rb, &ubi->ltree);
    + }
    + le->users += 1;
    + spin_unlock(&ubi->ltree_lock);
    +
    + if (le_free)
    + kmem_cache_free(ltree_slab, le_free);
    +
    + return le;
    +}
    +
    +/**
    + * leb_read_lock - lock logical eraseblock for reading.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + *
    + * This function locks a logical eraseblock for reading. Returns zero in case
    + * of success and a negative error code in case of failure.
    + */
    +static int leb_read_lock(struct ubi_device *ubi, int vol_id, int lnum)
    +{
    + struct ltree_entry *le;
    +
    + le = ltree_add_entry(ubi, vol_id, lnum);
    + if (unlikely(IS_ERR(le)))
    + return PTR_ERR(le);
    + down_read(&le->mutex);
    + return 0;
    +}
    +
    +/**
    + * leb_read_unlock - unlock logical eraseblock.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + */
    +static void leb_read_unlock(struct ubi_device *ubi, int vol_id, int lnum)
    +{
    + int free = 0;
    + struct ltree_entry *le;
    +
    + spin_lock(&ubi->ltree_lock);
    + le = ltree_lookup(ubi, vol_id, lnum);
    + le->users -= 1;
    + ubi_assert(le->users >= 0);
    + if (le->users == 0) {
    + rb_erase(&le->rb, &ubi->ltree);
    + free = 1;
    + }
    + spin_unlock(&ubi->ltree_lock);
    +
    + up_read(&le->mutex);
    + if (free)
    + kmem_cache_free(ltree_slab, le);
    +}
    +
    +/**
    + * leb_write_lock - lock logical eraseblock for writing.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + *
    + * This function locks a logical eraseblock for writing. Returns zero in case
    + * of success and a negative error code in case of failure.
    + */
    +static int leb_write_lock(struct ubi_device *ubi, int vol_id, int lnum)
    +{
    + struct ltree_entry *le;
    +
    + le = ltree_add_entry(ubi, vol_id, lnum);
    + if (unlikely(IS_ERR(le)))
    + return PTR_ERR(le);
    + down_write(&le->mutex);
    + return 0;
    +}
    +
    +/**
    + * leb_write_unlock - unlock logical eraseblock.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + */
    +static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
    +{
    + int free;
    + struct ltree_entry *le;
    +
    + spin_lock(&ubi->ltree_lock);
    + le = ltree_lookup(ubi, vol_id, lnum);
    + le->users -= 1;
    + ubi_assert(le->users >= 0);
    + if (le->users == 0) {
    + rb_erase(&le->rb, &ubi->ltree);
    + free = 1;
    + } else
    + free = 0;
    + spin_unlock(&ubi->ltree_lock);
    +
    + up_write(&le->mutex);
    + if (free)
    + kmem_cache_free(ltree_slab, le);
    +}
    +
    +/**
    + * ubi_eba_unmap_leb - un-map logical eraseblock.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + *
    + * This function un-maps logical eraseblock @lnum and schedules corresponding
    + * physical eraseblock for erasure. Returns zero in case of success and a
    + * negative error code in case of failure.
    + */
    +int ubi_eba_unmap_leb(struct ubi_device *ubi, int vol_id, int lnum)
    +{
    + int idx = vol_id2idx(ubi, vol_id), err, pnum;
    + struct ubi_volume *vol = ubi->volumes[idx];
    +
    + if (unlikely(ubi->ro_mode))
    + return -EROFS;
    +
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + pnum = vol->eba_tbl[lnum];
    + if (pnum < 0)
    + /* This logical eraseblock is already unmapped */
    + goto out_unlock;
    +
    + dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);
    +
    + vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
    + err = ubi_wl_put_peb(ubi, pnum, 0);
    +
    +out_unlock:
    + leb_write_unlock(ubi, vol_id, lnum);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_read_leb - read data.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + * @buf: buffer to store the read data
    + * @offset: offset from where to read
    + * @len: how many bytes to read
    + * @check: data CRC check flag
    + *
    + * If the logical eraseblock @lnum is unmapped, @buf is filled with 0xFF
    + * bytes. The @check flag only makes sense for static volumes and forces
    + * eraseblock data CRC checking.
    + *
    + * In case of success this function returns zero. In case of a static volume,
    + * if data CRC mismatches - %-EBADMSG is returned. %-EBADMSG may also be
    + * returned for any volume type if an ECC error was detected by the MTD device
    + * driver. Other negative error cored may be returned in case of other errors.
    + */
    +int ubi_eba_read_leb(struct ubi_device *ubi, int vol_id, int lnum, void *buf,
    + int offset, int len, int check)
    +{
    + int err, pnum, scrub = 0, idx = vol_id2idx(ubi, vol_id);
    + struct ubi_vid_hdr *vid_hdr;
    + struct ubi_volume *vol = ubi->volumes[idx];
    + uint32_t crc, crc1;
    +
    + err = leb_read_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + pnum = vol->eba_tbl[lnum];
    + if (pnum < 0) {
    + /*
    + * The logical eraseblock is not mapped, fill the whole buffer
    + * with 0xFF bytes. The exception is static volumes for which
    + * it is an error to read unmapped logical eraseblocks.
    + */
    + dbg_eba("read %d bytes from offset %d of LEB %d:%d (unmapped)",
    + len, offset, vol_id, lnum);
    + leb_read_unlock(ubi, vol_id, lnum);
    + ubi_assert(vol->vol_type != UBI_STATIC_VOLUME);
    + memset(buf, 0xFF, len);
    + return 0;
    + }
    +
    + dbg_eba("read %d bytes from offset %d of LEB %d:%d, PEB %d",
    + len, offset, vol_id, lnum, pnum);
    +
    + if (vol->vol_type == UBI_DYNAMIC_VOLUME)
    + check = 0;
    +
    +retry:
    + if (check) {
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (unlikely(!vid_hdr)) {
    + err = -ENOMEM;
    + goto out_unlock;
    + }
    +
    + err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
    + if (unlikely(err) && err != UBI_IO_BITFLIPS) {
    + if (err > 0) {
    + /*
    + * The header is either absent or corrupted.
    + * The former case means there is a bug -
    + * switch to read-only mode just in case.
    + * The latter case means a real corruption - we
    + * may try to recover data. FIXME: but this is
    + * not implemented.
    + */
    + if (err == UBI_IO_BAD_VID_HDR) {
    + ubi_warn("bad VID header at PEB %d, LEB"
    + "%d:%d", pnum, vol_id, lnum);
    + err = -EBADMSG;
    + } else
    + ubi_ro_mode(ubi);
    + }
    + goto out_free;
    + } else if (unlikely(err == UBI_IO_BITFLIPS))
    + scrub = 1;
    +
    + ubi_assert(lnum < ubi32_to_cpu(vid_hdr->used_ebs));
    + ubi_assert(len == ubi32_to_cpu(vid_hdr->data_size));
    +
    + crc = ubi32_to_cpu(vid_hdr->data_crc);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + }
    +
    + err = ubi_io_read_data(ubi, buf, pnum, offset, len);
    + if (unlikely(err)) {
    + if (err == UBI_IO_BITFLIPS) {
    + scrub = 1;
    + err = 0;
    + } else if (err == -EBADMSG) {
    + if (vol->vol_type == UBI_DYNAMIC_VOLUME)
    + goto out_unlock;
    + scrub = 1;
    + if (!check) {
    + ubi_msg("force data checking");
    + check = 1;
    + goto retry;
    + }
    + } else
    + goto out_unlock;
    + }
    +
    + if (check) {
    + crc1 = crc32(UBI_CRC32_INIT, buf, len);
    + if (unlikely(crc1 != crc)) {
    + ubi_warn("CRC error: calculated %#08x, must be %#08x",
    + crc1, crc);
    + err = -EBADMSG;
    + goto out_unlock;
    + }
    + }
    +
    + if (unlikely(scrub))
    + err = ubi_wl_scrub_peb(ubi, pnum);
    +
    + leb_read_unlock(ubi, vol_id, lnum);
    + return err;
    +
    +out_free:
    + ubi_free_vid_hdr(ubi, vid_hdr);
    +out_unlock:
    + leb_read_unlock(ubi, vol_id, lnum);
    + return err;
    +}
    +
    +/**
    + * recover_peb - recover from write failure.
    + * @ubi: UBI device description object
    + * @pnum: the physical eraseblock to recover
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + * @buf: data which was not written because of the write failure
    + * @offset: offset of the failed write
    + * @len: how many bytes should have been written
    + *
    + * This function is called in case of a write failure and moves all good data
    + * from the potentially bad physical eraseblock to a good physical eraseblock.
    + * This function also writes the data which was not written due to the failure.
    + * Returns new physical eraseblock number in case of success, and a negative
    + * error code in case of failure.
    + */
    +int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
    + const void *buf, int offset, int len)
    +{
    + int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0;
    + struct ubi_volume *vol = ubi->volumes[idx];
    + struct ubi_vid_hdr *vid_hdr;
    + unsigned char *new_buf;
    +
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (!vid_hdr) {
    + return -ENOMEM;
    + }
    +
    +retry:
    + new_pnum = ubi_wl_get_peb(ubi, UBI_DATA_UNKNOWN);
    + if (new_pnum < 0) {
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return new_pnum;
    + }
    +
    + ubi_msg("recover PEB %d, move data to PEB %d", pnum, new_pnum);
    +
    + err = ubi_io_read_vid_hdr(ubi, pnum, vid_hdr, 1);
    + if (err && err != UBI_IO_BITFLIPS) {
    + if (err > 0)
    + err = -EIO;
    + goto out_put;
    + }
    +
    + vid_hdr->sqnum = cpu_to_ubi64(next_sqnum(ubi));
    + err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
    + if (err)
    + goto write_error;
    +
    + data_size = offset + len;
    + new_buf = kmalloc(data_size, GFP_KERNEL);
    + if (unlikely(!new_buf)) {
    + err = -ENOMEM;
    + goto out_put;
    + }
    + memset(new_buf + offset, 0xFF, len);
    +
    + /* Read everything before the area where the write failure happened */
    + if (offset > 0) {
    + err = ubi_io_read_data(ubi, new_buf, pnum, 0, offset);
    + if (err && err != UBI_IO_BITFLIPS) {
    + kfree(new_buf);
    + goto out_put;
    + }
    + }
    +
    + memcpy(new_buf + offset, buf, len);
    +
    + err = ubi_io_write_data(ubi, new_buf, new_pnum, 0, data_size);
    + if (err) {
    + kfree(new_buf);
    + goto write_error;
    + }
    +
    + kfree(new_buf);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    +
    + vol->eba_tbl[lnum] = new_pnum;
    + ubi_wl_put_peb(ubi, pnum, 1);
    +
    + ubi_msg("data was successfully recovered");
    + return 0;
    +
    +out_put:
    + ubi_wl_put_peb(ubi, new_pnum, 1);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    +
    +write_error:
    + /*
    + * Bad luck? This physical eraseblock is bad too? Crud. Let's try to
    + * get another one.
    + */
    + ubi_warn("failed to write to PEB %d", new_pnum);
    + ubi_wl_put_peb(ubi, new_pnum, 1);
    + if (++tries > UBI_IO_RETRIES) {
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    + }
    + ubi_msg("try again");
    + goto retry;
    +}
    +
    +/**
    + * ubi_eba_write_leb - write data to dynamic volume.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + * @buf: the data to write
    + * @offset: offset within the logical eraseblock where to write
    + * @len: how many bytes to write
    + * @dtype: data type
    + *
    + * This function writes data to logical eraseblock @lnum of a dynamic volume
    + * @vol_id. Returns zero in case of success and a negative error code in case
    + * of failure. In case of error, it is possible that something was still
    + * written to the flash media, but may be some garbage.
    + */
    +int ubi_eba_write_leb(struct ubi_device *ubi, int vol_id, int lnum,
    + const void *buf, int offset, int len,
    + enum ubi_data_type dtype)
    +{
    + int idx = vol_id2idx(ubi, vol_id), err, pnum, tries = 0;
    + struct ubi_volume *vol = ubi->volumes[idx];
    + struct ubi_vid_hdr *vid_hdr;
    +
    + if (unlikely(ubi->ro_mode))
    + return -EROFS;
    +
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err))
    + return err;
    +
    + pnum = vol->eba_tbl[lnum];
    + if (pnum >= 0) {
    + dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
    + len, offset, vol_id, lnum, pnum);
    +
    + err = ubi_io_write_data(ubi, buf, pnum, offset, len);
    + if (unlikely(err)) {
    + ubi_warn("failed to write data to PEB %d", pnum);
    + if (err == -EIO && ubi->bad_allowed)
    + err = recover_peb(ubi, pnum, vol_id, lnum, buf, offset, len);
    + if (err)
    + ubi_ro_mode(ubi);
    + }
    + leb_write_unlock(ubi, vol_id, lnum);
    + return err;
    + }
    +
    + /*
    + * The logical eraseblock is not mapped. We have to get a free physical
    + * eraseblock and write the volume identifier header there first.
    + */
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (unlikely(!vid_hdr)) {
    + leb_write_unlock(ubi, vol_id, lnum);
    + return -ENOMEM;
    + }
    +
    + vid_hdr->vol_type = UBI_VID_DYNAMIC;
    + vid_hdr->sqnum = cpu_to_ubi64(next_sqnum(ubi));
    + vid_hdr->vol_id = cpu_to_ubi32(vol_id);
    + vid_hdr->lnum = cpu_to_ubi32(lnum);
    + vid_hdr->compat = ubi_get_compat(ubi, vol_id);
    + vid_hdr->data_pad = cpu_to_ubi32(vol->data_pad);
    +
    +retry:
    + pnum = ubi_wl_get_peb(ubi, dtype);
    + if (unlikely(pnum < 0)) {
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + leb_write_unlock(ubi, vol_id, lnum);
    + return pnum;
    + }
    +
    + dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
    + len, offset, vol_id, lnum, pnum);
    +
    + err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
    + if (unlikely(err)) {
    + ubi_warn("failed to write VID header to LEB %d:%d, PEB %d",
    + vol_id, lnum, pnum);
    + goto write_error;
    + }
    +
    + err = ubi_io_write_data(ubi, buf, pnum, offset, len);
    + if (unlikely(err)) {
    + ubi_warn("failed to write %d bytes at offset %d of LEB %d:%d, "
    + "PEB %d", len, offset, vol_id, lnum, pnum);
    + goto write_error;
    + }
    +
    + vol->eba_tbl[lnum] = pnum;
    +
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return 0;
    +
    +write_error:
    + if (err != -EIO || !ubi->bad_allowed) {
    + ubi_ro_mode(ubi);
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    + }
    +
    + /*
    + * Fortunately, this is the first write operation to this physical
    + * eraseblock, so just put it and request a new one. We assume that if
    + * this physical eraseblock went bad, the erase code will handle that.
    + */
    + err = ubi_wl_put_peb(ubi, pnum, 1);
    + if (err || ++tries > UBI_IO_RETRIES) {
    + ubi_ro_mode(ubi);
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    + }
    +
    + vid_hdr->sqnum = cpu_to_ubi64(next_sqnum(ubi));
    + ubi_msg("try another PEB");
    + goto retry;
    +}
    +
    +/**
    + * ubi_eba_write_leb_st - write data to static volume.
    + * @ubi: UBI device description object
    + * @vol_id: volume ID
    + * @lnum: logical eraseblock number
    + * @buf: data to write
    + * @len: how many bytes to write
    + * @dtype: data type
    + * @used_ebs: how many logical eraseblocks will this volume contain
    + *
    + * This function writes data to logical eraseblock @lnum of static volume
    + * @vol_id. The @used_ebs argument should contain total number of logical
    + * eraseblock in this static volume.
    + *
    + * When writing to the last logical eraseblock, the @len argument doesn't have
    + * to be aligned to the minimal I/O unit size. Instead, it has to be equivalent
    + * to the real data size, although the @buf buffer has to contain the
    + * alignment. In all other cases, @len has to be aligned.
    + *
    + * It is prohibited to write more then once to logical eraseblocks of static
    + * volumes. This function returns zero in case of success and a negative error
    + * code in case of failure.
    + */
    +int ubi_eba_write_leb_st(struct ubi_device *ubi, int vol_id, int lnum,
    + const void *buf, int len, enum ubi_data_type dtype,
    + int used_ebs)
    +{
    + int err, pnum, tries = 0, data_size = len;
    + int idx = vol_id2idx(ubi, vol_id);
    + struct ubi_volume *vol = ubi->volumes[idx];
    + struct ubi_vid_hdr *vid_hdr;
    + uint32_t crc;
    +
    + if (unlikely(ubi->ro_mode))
    + return -EROFS;
    +
    + if (lnum == used_ebs - 1)
    + /* If this is the last LEB @len may be unaligned */
    + len = ubi_align_up(data_size, ubi->min_io_size);
    + else
    + ubi_assert(len % ubi->min_io_size == 0);
    +
    + vid_hdr = ubi_zalloc_vid_hdr(ubi);
    + if (unlikely(!vid_hdr))
    + return -ENOMEM;
    +
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err)) {
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    + }
    +
    + vid_hdr->sqnum = cpu_to_ubi64(next_sqnum(ubi));
    + vid_hdr->vol_id = cpu_to_ubi32(vol_id);
    + vid_hdr->lnum = cpu_to_ubi32(lnum);
    + vid_hdr->compat = ubi_get_compat(ubi, vol_id);
    + vid_hdr->data_pad = cpu_to_ubi32(vol->data_pad);
    +
    + crc = crc32(UBI_CRC32_INIT, buf, data_size);
    + vid_hdr->vol_type = UBI_VID_STATIC;
    + vid_hdr->data_size = cpu_to_ubi32(data_size);
    + vid_hdr->used_ebs = cpu_to_ubi32(used_ebs);
    + vid_hdr->data_crc = cpu_to_ubi32(crc);
    +
    +retry:
    + pnum = ubi_wl_get_peb(ubi, dtype);
    + if (unlikely(pnum < 0)) {
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + leb_write_unlock(ubi, vol_id, lnum);
    + return pnum;
    + }
    +
    + dbg_eba("write VID hdr and %d bytes at LEB %d:%d, PEB %d, used_ebs %d",
    + len, vol_id, lnum, pnum, used_ebs);
    +
    + err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
    + if (unlikely(err)) {
    + ubi_warn("failed to write VID header to LEB %d:%d, PEB %d",
    + vol_id, lnum, pnum);
    + goto write_error;
    + }
    +
    + err = ubi_io_write_data(ubi, buf, pnum, 0, len);
    + if (unlikely(err)) {
    + ubi_warn("failed to write %d bytes of data to PEB %d",
    + len, pnum);
    + goto write_error;
    + }
    +
    + ubi_assert(vol->eba_tbl[lnum] < 0);
    + vol->eba_tbl[lnum] = pnum;
    +
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return 0;
    +
    +write_error:
    + if (err != -EIO || !ubi->bad_allowed) {
    + /*
    + * This flash device does not admit of bad eraseblocks or
    + * something nasty and unexpected happened. Switch to read-only
    + * mode just in case.
    + */
    + ubi_ro_mode(ubi);
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    + }
    +
    + err = ubi_wl_put_peb(ubi, pnum, 1);
    + if (err || ++tries > UBI_IO_RETRIES) {
    + ubi_ro_mode(ubi);
    + leb_write_unlock(ubi, vol_id, lnum);
    + ubi_free_vid_hdr(ubi, vid_hdr);
    + return err;
    + }
    +
    + vid_hdr->sqnum = cpu_to_ubi64(next_sqnum(ubi));
    + ubi_msg("try another PEB");
    + goto retry;
    +}
    +
    +/**
    + * ltree_entry_ctor - lock tree entries slab cache constructor.
    + * @obj: the lock-tree entry to construct
    + * @cache: the lock tree entry slab cache
    + * @flags: constructor flags
    + */
    +static void ltree_entry_ctor(void *obj, struct kmem_cache *cache,
    + unsigned long flags)
    +{
    + struct ltree_entry *le = obj;
    +
    + if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) !=
    + SLAB_CTOR_CONSTRUCTOR)
    + return;
    +
    + le->users = 0;
    + init_rwsem(&le->mutex);
    +}
    +
    +/**
    + * ubi_eba_copy_leb - copy logical eraseblock.
    + * @ubi: UBI device description object
    + * @from: physical eraseblock number from where to copy
    + * @to: physical eraseblock number where to copy
    + * @vid_hdr: VID header of the @from physical eraseblock
    + *
    + * This function copies logical eraseblock from physical eraseblock @from to
    + * physical eraseblock @to. The @vid_hdr buffer may be changed by this
    + * function. Returns zero in case of success, %UBI_IO_BITFLIPS if the operation
    + * was canceled because bit-flips were detected at the target PEB, and a
    + * negative error code in case of failure.
    + */
    +int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
    + struct ubi_vid_hdr *vid_hdr)
    +{
    + int err, vol_id, lnum, data_size, aldata_size, pnum, idx;
    + struct ubi_volume *vol;
    + uint32_t crc;
    + void *buf, *buf1 = NULL;
    +
    + vol_id = ubi32_to_cpu(vid_hdr->vol_id);
    + lnum = ubi32_to_cpu(vid_hdr->lnum);
    +
    + dbg_eba("copy LEB %d:%d, PEB %d to PEB %d", vol_id, lnum, from, to);
    +
    + if (vid_hdr->vol_type == UBI_VID_STATIC) {
    + data_size = ubi32_to_cpu(vid_hdr->data_size);
    + aldata_size = ubi_align_up(data_size, ubi->min_io_size);
    + } else
    + data_size = aldata_size =
    + ubi->leb_size - ubi32_to_cpu(vid_hdr->data_pad);
    +
    + buf = kmalloc(aldata_size, GFP_KERNEL);
    + if (unlikely(!buf))
    + return -ENOMEM;
    +
    + /*
    + * We do not want anybody to write to this logical eraseblock while we
    + * are moving it, so we lock it.
    + */
    + err = leb_write_lock(ubi, vol_id, lnum);
    + if (unlikely(err)) {
    + kfree(buf);
    + return err;
    + }
    +
    + /*
    + * But the logical eraseblock might have been put by this time.
    + * Cancel if it is true.
    + */
    + idx = vol_id2idx(ubi, vol_id);
    +
    + /*
    + * We may race with volume deletion/resize, so we have to hold
    + * @ubi->volumes_lock.
    + */
    + spin_lock(&ubi->volumes_lock);
    + vol = ubi->volumes[idx];
    + if (!vol) {
    + dbg_eba("volume %d was removed meanwhile", vol_id);
    + spin_unlock(&ubi->volumes_lock);
    + goto out_unlock;
    + }
    +
    + pnum = vol->eba_tbl[lnum];
    + if (pnum != from) {
    + dbg_eba("LEB %d:%d is no longer mapped to PEB %d, mapped to "
    + "PEB %d, cancel", vol_id, lnum, from, pnum);
    + spin_unlock(&ubi->volumes_lock);
    + goto out_unlock;
    + }
    + spin_unlock(&ubi->volumes_lock);
    +
    + /* OK, now the LEB is locked and we can safely start moving it */
    +
    + dbg_eba("read %d bytes of data", aldata_size);
    + err = ubi_io_read_data(ubi, buf, from, 0, aldata_size);
    + if (unlikely(err) && err != UBI_IO_BITFLIPS) {
    + ubi_warn("error %d while reading data from PEB %d",
    + err, from);
    + goto out_unlock;
    + }
    +
    + /*
    + * Now we have got to calculate how much data we have to to copy. In
    + * case of a static volume it is fairly easy - the VID header contains
    + * the data size. In case of a dynamic volume it is more difficult - we
    + * have to read the contents, cut 0xFF bytes from the end and copy only
    + * the first part. We must do this to avoid writing 0xFF bytes as it
    + * may have some side-effects. And not only this. It is important not
    + * to include those 0xFFs to CRC because later the they may be filled
    + * by data.
    + */
    + if (vid_hdr->vol_type == UBI_VID_DYNAMIC)
    + aldata_size = data_size =
    + ubi_calc_data_len(ubi, buf, data_size);
    +
    + cond_resched();
    + crc = crc32(UBI_CRC32_INIT, buf, data_size);
    + cond_resched();
    +
    + /*
    + * It may turn out to me that the whole @from physical eraseblock
    + * contains only 0xFF bytes. Then we have to only write the VID header
    + * and do not write any data. This also means we should not set
    + * @vid_hdr->copy_flag, @vid_hdr->data_size, and @vid_hdr->data_crc.
    + */
    + if (likely(data_size > 0)) {
    + vid_hdr->copy_flag = 1;
    + vid_hdr->data_size = cpu_to_ubi32(data_size);
    + vid_hdr->data_crc = cpu_to_ubi32(crc);
    + }
    + vid_hdr->sqnum = cpu_to_ubi64(next_sqnum(ubi));
    +
    + err = ubi_io_write_vid_hdr(ubi, to, vid_hdr);
    + if (unlikely(err))
    + goto out_unlock;
    +
    + cond_resched();
    +
    + /* Read the VID header back and check if it was written correctly */
    + err = ubi_io_read_vid_hdr(ubi, to, vid_hdr, 1);
    + if (unlikely(err)) {
    + if (err != UBI_IO_BITFLIPS)
    + ubi_warn("cannot read VID header back from PEB %d", to);
    + goto out_unlock;
    + }
    +
    + if (likely(data_size > 0)) {
    + err = ubi_io_write_data(ubi, buf, to, 0, aldata_size);
    + if (unlikely(err))
    + goto out_unlock;
    +
    + /*
    + * We've written the data and are going to read it back to make
    + * sure it was written correctly.
    + */
    + buf1 = kmalloc(aldata_size, GFP_KERNEL);
    + if (unlikely(!buf1)) {
    + err = -ENOMEM;
    + goto out_unlock;
    + }
    +
    + cond_resched();
    +
    + err = ubi_io_read_data(ubi, buf1, to, 0, aldata_size);
    + if (unlikely(err)) {
    + if (err != UBI_IO_BITFLIPS)
    + ubi_warn("cannot read data back from PEB %d",
    + to);
    + goto out_unlock;
    + }
    +
    + cond_resched();
    +
    + if (unlikely(memcmp(buf, buf1, aldata_size))) {
    + ubi_warn("read data back from PEB %d - it is different",
    + to);
    + goto out_unlock;
    + }
    + }
    +
    + ubi_assert(vol->eba_tbl[lnum] == from);
    + vol->eba_tbl[lnum] = to;
    +
    + leb_write_unlock(ubi, vol_id, lnum);
    + kfree(buf);
    + kfree(buf1);
    +
    + return 0;
    +
    +out_unlock:
    + leb_write_unlock(ubi, vol_id, lnum);
    + kfree(buf);
    + kfree(buf1);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_init_scan - initialize the EBA unit using scanning information.
    + * @ubi: UBI device description object
    + * @si: scanning information
    + *
    + * This function returns zero in case of success and a negative error code in
    + * case of failure.
    + */
    +int ubi_eba_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si)
    +{
    + int i, j, err, num_volumes;
    + struct ubi_scan_volume *sv;
    + struct ubi_volume *vol;
    + struct ubi_scan_leb *seb;
    + struct rb_node *rb;
    +
    + dbg_eba("initialize EBA unit");
    +
    + spin_lock_init(&ubi->ltree_lock);
    + ubi->ltree = RB_ROOT;
    +
    + if (ubi_devices_cnt == 0) {
    + ltree_slab = kmem_cache_create("ubi_ltree_slab",
    + sizeof(struct ltree_entry), 0,
    + 0, &ltree_entry_ctor, NULL);
    + if (!ltree_slab)
    + return -ENOMEM;
    + }
    +
    + ubi->global_sqnum = si->max_sqnum + 1;
    + num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
    +
    + for (i = 0; i < num_volumes; i++) {
    + vol = ubi->volumes[i];
    + if (!vol)
    + continue;
    +
    + cond_resched();
    +
    + vol->eba_tbl = kmalloc(vol->reserved_pebs * sizeof(int),
    + GFP_KERNEL);
    + if (unlikely(!vol->eba_tbl)) {
    + err = -ENOMEM;
    + goto out_free;
    + }
    +
    + for (j = 0; j < vol->reserved_pebs; j++)
    + vol->eba_tbl[j] = UBI_LEB_UNMAPPED;
    +
    + sv = ubi_scan_find_sv(si, idx2vol_id(ubi, i));
    + if (!sv)
    + continue;
    +
    + ubi_rb_for_each_entry(rb, seb, &sv->root, u.rb) {
    + if (seb->lnum >= vol->reserved_pebs)
    + /*
    + * This may happen in case of an unclean reboot
    + * during re-size.
    + */
    + ubi_scan_move_to_list(sv, seb, &si->erase);
    + vol->eba_tbl[seb->lnum] = seb->pnum;
    + }
    + }
    +
    + if (ubi->bad_allowed) {
    + ubi_calculate_reserved(ubi);
    +
    + if (ubi->avail_pebs < ubi->beb_rsvd_level) {
    + /* No enough free physical eraseblocks */
    + ubi->beb_rsvd_pebs = ubi->avail_pebs;
    + ubi_warn("cannot reserve enough PEBs for bad PEB "
    + "handling, reserved %d, need %d",
    + ubi->beb_rsvd_pebs, ubi->beb_rsvd_level);
    + } else
    + ubi->beb_rsvd_pebs = ubi->beb_rsvd_level;
    +
    + ubi->avail_pebs -= ubi->beb_rsvd_pebs;
    + ubi->rsvd_pebs += ubi->beb_rsvd_pebs;
    + }
    +
    + dbg_eba("EBA unit is initialized");
    + return 0;
    +
    +out_free:
    + for (i = 0; i < num_volumes; i++) {
    + if (!ubi->volumes[i])
    + continue;
    + kfree(ubi->volumes[i]->eba_tbl);
    + }
    + if (ubi_devices_cnt == 0)
    + kmem_cache_destroy(ltree_slab);
    + return err;
    +}
    +
    +/**
    + * ubi_eba_close - close EBA unit.
    + * @ubi: UBI device description object
    + */
    +void ubi_eba_close(const struct ubi_device *ubi)
    +{
    + int i, num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;
    +
    + dbg_eba("close EBA unit");
    +
    + for (i = 0; i < num_volumes; i++) {
    + if (!ubi->volumes[i])
    + continue;
    + kfree(ubi->volumes[i]->eba_tbl);
    + }
    + if (ubi_devices_cnt == 1)
    + kmem_cache_destroy(ltree_slab);
    +}
    -
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      Last update: 2007-03-23 17:49    [W:0.093 / U:0.628 seconds]
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